見た目の美しさに影響を与えずにキーボードのみのフォーカス スタイルを実現するにはどうすればよいですか?

<code class="css">button:focus-visible {
  /* remove default focus style */
  outline: none;
  /* custom focus styles */
  box-shadow: 0 0 2px 2px #51a7e8;
  color: lime;
}</code>

<code class="css">button:focus {
  outline: none;
  background: #ffdd00; /* gold */
}

button:focus:not(:focus-visible) {
  background: white; /* undo gold */
}</code>

<code class="css">button {
  -moz-appearance: none;
  -webkit-appearance: none;
  background: none;
  border: none;
  outline: none;
  font-size: inherit;
}

.btn {
  all: initial;
  margin: 1em;
  display: inline-block; 
}

.btn__content {
  background: orange;
  padding: 1em;
  cursor: pointer;
  display: inline-block;
}


/* Fixing the Safari bug for `<button>`s overflow */
.btn__content {
    position: relative;
}

/* All the states on the inner element */
.btn:hover > .btn__content  {
    background: salmon;
}

.btn:active > .btn__content  {
    background: darkorange;
}

.btn:focus > .btn__content  {
    box-shadow: 0 0 2px 2px #51a7e8;
    color: lime;
}

/* Removing default outline only after we've added our custom one */
.btn:focus,
.btn__content:focus {
    outline: none;
}</code>